Modern systems for industrial cutting comprise several motorized cutting systems, each of which has a plurality of cutters arranged side-by-side and actuated simultaneously by devices which can have an electromagnetic, pneumatic or other operating principle and operate continuously even for three eight-hour shifts, seven days a week, as in the case of paper industries. Currently, scissor-type or pressure-type devices are mostly used to cut laminates, for example paper, plastics, aluminum, two-part elements, and fibers of any sort, from non-wovens to carbon fiber. These devices use a circular cutter, which is mounted on an appropriate cutter holder, which acts by lateral contact with a complementary rotating cutter, in the case of scissor-type cutting, or directly by pressing on the material to be cut, which advances on a contrast roller, in the case of pressure cutting.
A cutter holder of this type is constituted generally by a fixed part, which is installed on the supports, which in turn are fitted on a sliding guide of the industrial cutting machine, which is known as cutter holder body, and by a movable part, known as cartridge, on which the circular cutter is fitted. Such cartridge is engaged detachably on the body of the cutter holder, which is provided with a suitable coupling, and must be removed from it whenever it is necessary to perform maintenance on the blade of the cutter or replace it. Since the cutter holder and the cartridge must work as if they were monolithic with each other, in order to ensure precise and constant execution of the cut over time, the mechanical stresses to which the cutter holder is subjected must not be discharged asymmetrically onto said coupling, on penalty of higher wear of the device and also of the occurrence of dangerous weaknesses. For this reason, the coupling of the cartridge on the cutter holder must be conceived and provided so as to be at once durable and rational for the user, who by means of simple and repeatable actions, and in full safety, must be able to extract the cartridge and reinsert it subsequently, fixing it firmly to the cutter holder body.
Various kinds of coupling of the cartridge on the cutter holder body are known. EP-0562454 discloses a cutting unit for the longitudinal cutting of flexible materials, such as for example paper strips, which is provided with means which allow rapid replacement of the blade holder head. Such head is connected to a vertical pivot, which enters the body of the blade holder and around which said head can turn up to 180°, i.e., perform a reversal. The blade holder head is provided with a T-shaped element, the longer external side of which has a lower portion which receives and locks the arm of the fork, while the shorter side and a side which is adjacent and perpendicular thereto make contact and are locked by means of a screw. By unscrewing such screw, the blade holder head can be removed. Although such a mechanism fully achieves the intended aim, it has certain limitations. First of all, it requires the user to loosen a screw, an operation which is not exactly fast, and especially to act manually in the immediate vicinity of the blade of the cutter, thus exposing himself to the risk of injury, although a housing for partial protection is provided on the circumference of the blade in the inactive condition. Moreover, the head reversal operation does not occur by reversing the position of the head but by way of the rotation of the stem to which the cartridge is coupled, and this occurs by means of appropriate controls located on the upper portion of the cutter holder body.
U.S. Pat. No. 6,732,625 discloses a cutter holder in which the engagement and removal of the cartridge occur by means of a slider with a dovetail profile, which is provided on the body of the cutter holder and on which the cartridge is engaged horizontally, a slot provided with a complementarily shaped profile being provided for this purpose on the head portion of the cartridge. A locking device is also present which can be activated and deactivated manually and consists of a lever provided with a cam, which, when turned about a pivot, pushes with the cam in an oblique direction a locking bar, which like a wedge locks the cartridge on the cutter holder. This mechanism simplifies the removal and reengagement of the cartridge and also allows to turn through 180° the blade of the cutter simply by extracting the cartridge and reinserting it in the inverted position. However, the resulting type of locking is not symmetrical on both sides of the dovetail slider of the cartridge. Moreover, the contact between the pneumatic ducts of the cutter holder body and of the cartridge, which are required in order to allow the partial approach and full approach of the blade, might not maintain a perfect coupling, since a uniform contact pressure between the corresponding horizontal surfaces of the body of the cutter holder and of the cartridge head portion is not provided.